From 00a0ce9082b4cc1389815defcc806efd4a9b80f4 Mon Sep 17 00:00:00 2001 From: Greg Brown Date: Mon, 18 Apr 2022 15:05:24 +0100 Subject: Do a big refactor. - Replace the decidable predicates on expressions and statements with separate data types. - Reorganise the Hoare logic semantics to remove unnecessary definitions. - Make liberal use of modules to group related definitions together. - Unify the types for denotational and Hoare logic semantics. - Make bits an abstraction of array types. --- src/Helium/Data/Pseudocode/Core.agda | 522 +++++++++++++++-------------------- 1 file changed, 222 insertions(+), 300 deletions(-) (limited to 'src/Helium/Data/Pseudocode/Core.agda') diff --git a/src/Helium/Data/Pseudocode/Core.agda b/src/Helium/Data/Pseudocode/Core.agda index 079e2ce..579d68d 100644 --- a/src/Helium/Data/Pseudocode/Core.agda +++ b/src/Helium/Data/Pseudocode/Core.agda @@ -11,20 +11,18 @@ module Helium.Data.Pseudocode.Core where open import Data.Bool using (Bool; true; false) open import Data.Fin as Fin using (Fin) open import Data.Fin.Patterns +open import Data.Integer as ℤ using (ℤ) open import Data.Nat as ℕ using (ℕ; zero; suc) open import Data.Nat.Properties using (+-comm) -open import Data.Product using (∃; _,_; proj₂; uncurry) -open import Data.Sum using ([_,_]′; inj₁; inj₂) +open import Data.Product using (_×_; _,_) +open import Data.Unit using (⊤) open import Data.Vec using (Vec; []; _∷_; lookup; map) -open import Data.Vec.Relation.Unary.All using (All; []; _∷_; reduce) -open import Data.Vec.Relation.Unary.Any using (Any; here; there) -open import Function as F using (_∘_; _∘′_; _∋_) -open import Relation.Binary.PropositionalEquality using (_≡_; refl) -open import Relation.Nullary using (Dec; yes; no) -open import Relation.Nullary.Decidable.Core using (True; False; toWitness; fromWitness; map′) -open import Relation.Nullary.Product using (_×-dec_) -open import Relation.Nullary.Sum using (_⊎-dec_) -open import Relation.Unary using (Decidable) +open import Data.Vec.Relation.Unary.All using (All; []; _∷_) +open import Relation.Binary.PropositionalEquality using (_≡_) + +private + variable + k m n o : ℕ --- The set of types and boolean properties of them data Type : Set where @@ -33,297 +31,221 @@ data Type : Set where fin : (n : ℕ) → Type real : Type bit : Type - bits : (n : ℕ) → Type - tuple : ∀ n → Vec Type n → Type + tuple : Vec Type n → Type array : Type → (n : ℕ) → Type +bits : ℕ → Type +bits = array bit + +private + variable + t t′ t₁ t₂ : Type + Σ Γ Δ ts : Vec Type n + data HasEquality : Type → Set where - bool : HasEquality bool - int : HasEquality int - fin : ∀ {n} → HasEquality (fin n) - real : HasEquality real - bit : HasEquality bit - bits : ∀ {n} → HasEquality (bits n) - -hasEquality? : Decidable HasEquality -hasEquality? bool = yes bool -hasEquality? int = yes int -hasEquality? (fin n) = yes fin -hasEquality? real = yes real -hasEquality? bit = yes bit -hasEquality? (bits n) = yes bits -hasEquality? (tuple n x) = no (λ ()) -hasEquality? (array t n) = no (λ ()) + instance bool : HasEquality bool + instance int : HasEquality int + instance fin : HasEquality (fin n) + instance real : HasEquality real + instance bit : HasEquality bit + instance array : ∀ {t n} → ⦃ HasEquality t ⦄ → HasEquality (array t n) + +data Ordered : Type → Set where + instance int : Ordered int + instance fin : Ordered (fin n) + instance real : Ordered real data IsNumeric : Type → Set where - int : IsNumeric int - real : IsNumeric real - -isNumeric? : Decidable IsNumeric -isNumeric? bool = no (λ ()) -isNumeric? int = yes int -isNumeric? (fin n) = no (λ ()) -isNumeric? real = yes real -isNumeric? bit = no (λ ()) -isNumeric? (bits n) = no (λ ()) -isNumeric? (tuple n x) = no (λ ()) -isNumeric? (array t n) = no (λ ()) - -combineNumeric : ∀ t₁ t₂ → (isNumeric₁ : True (isNumeric? t₁)) → (isNumeric₂ : True (isNumeric? t₂)) → Type -combineNumeric int int _ _ = int -combineNumeric int real _ _ = real -combineNumeric real _ _ _ = real - -data Sliced : Set where - bits : Sliced - array : Type → Sliced - -asType : Sliced → ℕ → Type -asType bits n = bits n -asType (array t) n = array t n - -elemType : Sliced → Type -elemType bits = bit -elemType (array t) = t - ---- Literals - -data Literal : Type → Set where - _′b : Bool → Literal bool - _′i : ℕ → Literal int - _′f : ∀ {n} → Fin n → Literal (fin n) - _′r : ℕ → Literal real - _′x : Bool → Literal bit - _′xs : ∀ {n} → Vec Bool n → Literal (bits n) - _′a : ∀ {n t} → Literal t → Literal (array t n) - ---- Expressions, references, statements, functions and procedures - -module Code {o} (Σ : Vec Type o) where - data Expression {n} (Γ : Vec Type n) : Type → Set - data CanAssign {n Γ} : ∀ {t} → Expression {n} Γ t → Set - canAssign? : ∀ {n Γ t} → Decidable (CanAssign {n} {Γ} {t}) - data ReferencesState {n Γ} : ∀ {t} → Expression {n} Γ t → Set - referencesState? : ∀ {n Γ t} → Decidable (ReferencesState {n} {Γ} {t}) - data Statement {n} (Γ : Vec Type n) : Set - data ChangesState {n Γ} : Statement {n} Γ → Set - changesState? : ∀ {n Γ} → Decidable (ChangesState {n} {Γ}) - data Function {n} (Γ : Vec Type n) (ret : Type) : Set - data Procedure {n} (Γ : Vec Type n) : Set - - infix 8 -_ - infixr 7 _^_ - infixl 6 _*_ _and_ _>>_ - -- infixl 6 _/_ - infixl 5 _+_ _or_ _&&_ _||_ - infix 4 _≟_ _>_ : Expression Γ int → ℕ → Expression Γ int - rnd : Expression Γ real → Expression Γ int - fin : ∀ {k ms n} → (All (Fin) ms → Fin n) → Expression Γ (tuple k (map fin ms)) → Expression Γ (fin n) - asInt : ∀ {m} → Expression Γ (fin m) → Expression Γ int - nil : Expression Γ (tuple 0 []) - cons : ∀ {m t ts} → Expression Γ t → Expression Γ (tuple m ts) → Expression Γ (tuple (suc m) (t ∷ ts)) - head : ∀ {m t ts} → Expression Γ (tuple (suc m) (t ∷ ts)) → Expression Γ t - tail : ∀ {m t ts} → Expression Γ (tuple (suc m) (t ∷ ts)) → Expression Γ (tuple m ts) - call : ∀ {t m Δ} → Function Δ t → All (Expression Γ) {m} Δ → Expression Γ t - if_then_else_ : ∀ {t} → Expression Γ bool → Expression Γ t → Expression Γ t → Expression Γ t - - data CanAssign {n} {Γ} where - state : ∀ i → CanAssign (state i) - var : ∀ i → CanAssign (var i) - abort : ∀ {t} e → CanAssign (abort {t = t} e) - [_] : ∀ {t e} → CanAssign e → CanAssign ([_] {t = t} e) - unbox : ∀ {t e} → CanAssign e → CanAssign (unbox {t = t} e) - splice : ∀ {m n t e₁ e₂} → CanAssign e₁ → CanAssign e₂ → ∀ e₃ → CanAssign (splice {m = m} {n} {t} e₁ e₂ e₃) - cut : ∀ {m n t e₁} → CanAssign e₁ → ∀ e₂ → CanAssign (cut {m = m} {n} {t} e₁ e₂) - cast : ∀ {i j t e} .(eq : i ≡ j) → CanAssign e → CanAssign (cast {t = t} eq e) - nil : CanAssign nil - cons : ∀ {m t ts e₁ e₂} → CanAssign e₁ → CanAssign e₂ → CanAssign (cons {m = m} {t} {ts} e₁ e₂) - head : ∀ {m t ts e} → CanAssign e → CanAssign (head {m = m} {t} {ts} e) - tail : ∀ {m t ts e} → CanAssign e → CanAssign (tail {m = m} {t} {ts} e) - - canAssign? (lit x) = no λ () - canAssign? (state i) = yes (state i) - canAssign? (var i) = yes (var i) - canAssign? (abort e) = yes (abort e) - canAssign? (e ≟ e₁) = no λ () - canAssign? (e > e₁) = no λ () - canAssign? (rnd e) = no λ () - canAssign? (fin x e) = no λ () - canAssign? (asInt e) = no λ () - canAssign? nil = yes nil - canAssign? (cons e e₁) = map′ (uncurry cons) (λ { (cons e e₁) → e , e₁ }) (canAssign? e ×-dec canAssign? e₁) - canAssign? (head e) = map′ head (λ { (head e) → e }) (canAssign? e) - canAssign? (tail e) = map′ tail (λ { (tail e) → e }) (canAssign? e) - canAssign? (call x e) = no λ () - canAssign? (if e then e₁ else e₂) = no λ () - - data ReferencesState where - state : ∀ i → ReferencesState (state i) - [_] : ∀ {t e} → ReferencesState e → ReferencesState ([_] {t = t} e) - unbox : ∀ {t e} → ReferencesState e → ReferencesState (unbox {t = t} e) - spliceˡ : ∀ {m n t e} → ReferencesState e → ∀ e₁ e₂ → ReferencesState (splice {m = m} {n} {t} e e₁ e₂) - spliceʳ : ∀ {m n t} e {e₁} → ReferencesState e₁ → ∀ e₂ → ReferencesState (splice {m = m} {n} {t} e e₁ e₂) - cut : ∀ {m n t e} → ReferencesState e → ∀ e₁ → ReferencesState (cut {m = m} {n} {t} e e₁) - cast : ∀ {i j t} .(eq : i ≡ j) {e} → ReferencesState e → ReferencesState (cast {t = t} eq e) - consˡ : ∀ {m t ts e} → ReferencesState e → ∀ e₁ → ReferencesState (cons {m = m} {t} {ts} e e₁) - consʳ : ∀ {m t ts} e {e₁} → ReferencesState e₁ → ReferencesState (cons {m = m} {t} {ts} e e₁) - head : ∀ {m t ts e} → ReferencesState e → ReferencesState (head {m = m} {t} {ts} e) - tail : ∀ {m t ts e} → ReferencesState e → ReferencesState (tail {m = m} {t} {ts} e) - - referencesState? (lit x) = no λ () - referencesState? (state i) = yes (state i) - referencesState? (var i) = no λ () - referencesState? (abort e) = no λ () - referencesState? (e ≟ e₁) = no λ () - referencesState? (e > x) = no λ () - referencesState? (rnd e) = no λ () - referencesState? (fin x e) = no λ () - referencesState? (asInt e) = no λ () - referencesState? nil = no λ () - referencesState? (cons e e₁) = map′ [ (λ e → consˡ e e₁) , (λ e₁ → consʳ e e₁) ]′ (λ { (consˡ e e₁) → inj₁ e ; (consʳ e e₁) → inj₂ e₁ }) (referencesState? e ⊎-dec referencesState? e₁) - referencesState? (head e) = map′ head (λ { (head e) → e }) (referencesState? e) - referencesState? (tail e) = map′ tail (λ { (tail e) → e }) (referencesState? e) - referencesState? (call f es) = no λ () - referencesState? (if e then e₁ else e₂) = no λ () - - infix 4 _≔_ - infixl 2 if_then_else_ if_then_ - infixl 1 _∙_ _∙return_ - infix 1 _∙end - - data Statement Γ where - _∙_ : Statement Γ → Statement Γ → Statement Γ - skip : Statement Γ - _≔_ : ∀ {t} → (ref : Expression Γ t) → {canAssign : True (canAssign? ref)} → Expression Γ t → Statement Γ - declare : ∀ {t} → Expression Γ t → Statement (t ∷ Γ) → Statement Γ - invoke : ∀ {m Δ} → Procedure Δ → All (Expression Γ) {m} Δ → Statement Γ - if_then_ : Expression Γ bool → Statement Γ → Statement Γ - if_then_else_ : Expression Γ bool → Statement Γ → Statement Γ → Statement Γ - for : ∀ m → Statement (fin m ∷ Γ) → Statement Γ - - data ChangesState where - _∙ˡ_ : ∀ {s} → ChangesState s → ∀ s₁ → ChangesState (s ∙ s₁) - _∙ʳ_ : ∀ s {s₁} → ChangesState s₁ → ChangesState (s ∙ s₁) - _≔_ : ∀ {t} ref {canAssign : True (canAssign? ref)} {refsState : True (referencesState? ref)} e₂ → ChangesState (_≔_ {t = t} ref {canAssign} e₂) - declare : ∀ {t} e {s} → ChangesState s → ChangesState (declare {t = t} e s) - invoke : ∀ {m Δ} p es → ChangesState (invoke {m = m} {Δ} p es) - if_then_ : ∀ e {s} → ChangesState s → ChangesState (if e then s) - if_then′_else_ : ∀ e {s} → ChangesState s → ∀ s₁ → ChangesState (if e then s else s₁) - if_then_else′_ : ∀ e s {s₁} → ChangesState s₁ → ChangesState (if e then s else s₁) - for : ∀ m {s} → ChangesState s → ChangesState (for m s) - - changesState? (s ∙ s₁) = map′ [ _∙ˡ s₁ , s ∙ʳ_ ]′ (λ { (s ∙ˡ s₁) → inj₁ s ; (s ∙ʳ s₁) → inj₂ s₁ }) (changesState? s ⊎-dec changesState? s₁) - changesState? skip = no λ () - changesState? (_≔_ ref e) = map′ (λ refsState → _≔_ ref {refsState = fromWitness refsState} e) (λ { (_≔_ ref {refsState = refsState} e) → toWitness refsState }) (referencesState? ref) - changesState? (declare e s) = map′ (declare e) (λ { (declare e s) → s }) (changesState? s) - changesState? (invoke p e) = yes (invoke p e) - changesState? (if e then s) = map′ (if e then_) (λ { (if e then s) → s }) (changesState? s) - changesState? (if e then s else s₁) = map′ [ if e then′_else s₁ , if e then s else′_ ]′ (λ { (if e then′ s else s₁) → inj₁ s ; (if e then s else′ s₁) → inj₂ s₁ }) (changesState? s ⊎-dec changesState? s₁) - changesState? (for m s) = map′ (for m) (λ { (for m s) → s }) (changesState? s) - - data Function Γ ret where - _∙return_ : (s : Statement Γ) → {False (changesState? s)} → Expression Γ ret → Function Γ ret - declare : ∀ {t} → Expression Γ t → Function (t ∷ Γ) ret → Function Γ ret - - data Procedure Γ where - _∙end : Statement Γ → Procedure Γ - - infixl 6 _<<_ - infixl 5 _-_ _∶_ - - tup : ∀ {n Γ m ts} → All (Expression {n} Γ) ts → Expression Γ (tuple m ts) - tup [] = nil - tup (e ∷ es) = cons e (tup es) - - _∶_ : ∀ {n Γ i j t} → Expression {n} Γ (asType t j) → Expression Γ (asType t i) → Expression Γ (asType t (i ℕ.+ j)) - e₁ ∶ e₂ = splice e₁ e₂ (lit (Fin.fromℕ _ ′f)) - - slice : ∀ {n Γ i j t} → Expression {n} Γ (asType t (i ℕ.+ j)) → Expression Γ (fin (suc i)) → Expression Γ (asType t j) - slice e₁ e₂ = head (cut e₁ e₂) - - slice′ : ∀ {n Γ i j t} → Expression {n} Γ (asType t (i ℕ.+ j)) → Expression Γ (fin (suc j)) → Expression Γ (asType t i) - slice′ {i = i} e₁ e₂ = slice (cast (+-comm i _) e₁) e₂ - - _-_ : ∀ {n Γ t₁ t₂} {isNumeric₁ : True (isNumeric? t₁)} {isNumeric₂ : True (isNumeric? t₂)} → Expression {n} Γ t₁ → Expression Γ t₂ → Expression Γ (combineNumeric t₁ t₂ isNumeric₁ isNumeric₂) - _-_ {isNumeric₂ = isNumeric₂} x y = x + (-_ {isNumeric = isNumeric₂} y) - - _<<_ : ∀ {n Γ} → Expression {n} Γ int → ℕ → Expression Γ int - x << n = rnd (x * lit (2 ′r) ^ n) - - get : ∀ {n Γ} → ℕ → Expression {n} Γ int → Expression Γ bit - get i x = if x - x >> suc i << suc i >_ +infixl 5 _+_ _or_ _&&_ _||_ +infix 4 _≟_ _>_ : Expression Σ Γ int → (n : ℕ) → Expression Σ Γ int + rnd : Expression Σ Γ real → Expression Σ Γ int + fin : ∀ {ms} (f : literalTypes (map fin ms) → Fin n) → Expression Σ Γ (tuple {n = k} (map fin ms)) → Expression Σ Γ (fin n) + asInt : Expression Σ Γ (fin n) → Expression Σ Γ int + nil : Expression Σ Γ (tuple []) + cons : Expression Σ Γ t → Expression Σ Γ (tuple ts) → Expression Σ Γ (tuple (t ∷ ts)) + head : Expression Σ Γ (tuple (t ∷ ts)) → Expression Σ Γ t + tail : Expression Σ Γ (tuple (t ∷ ts)) → Expression Σ Γ (tuple ts) + call : (f : Function Σ Δ t) → All (Expression Σ Γ) Δ → Expression Σ Γ t + if_then_else_ : Expression Σ Γ bool → Expression Σ Γ t → Expression Σ Γ t → Expression Σ Γ t + +data Reference Σ Γ where + state : ∀ i → Reference Σ Γ (lookup Σ i) + var : ∀ i → Reference Σ Γ (lookup Γ i) + [_] : Reference Σ Γ t → Reference Σ Γ (array t 1) + unbox : Reference Σ Γ (array t 1) → Reference Σ Γ t + merge : Reference Σ Γ (array t m) → Reference Σ Γ (array t n) → Expression Σ Γ (fin (suc n)) → Reference Σ Γ (array t (n ℕ.+ m)) + slice : Reference Σ Γ (array t (n ℕ.+ m)) → Expression Σ Γ (fin (suc n)) → Reference Σ Γ (array t m) + cut : Reference Σ Γ (array t (n ℕ.+ m)) → Expression Σ Γ (fin (suc n)) → Reference Σ Γ (array t n) + cast : .(eq : m ≡ n) → Reference Σ Γ (array t m) → Reference Σ Γ (array t n) + nil : Reference Σ Γ (tuple []) + cons : Reference Σ Γ t → Reference Σ Γ (tuple ts) → Reference Σ Γ (tuple (t ∷ ts)) + head : Reference Σ Γ (tuple (t ∷ ts)) → Reference Σ Γ t + tail : Reference Σ Γ (tuple (t ∷ ts)) → Reference Σ Γ (tuple ts) + +data LocalReference Σ Γ where + var : ∀ i → LocalReference Σ Γ (lookup Γ i) + [_] : LocalReference Σ Γ t → LocalReference Σ Γ (array t 1) + unbox : LocalReference Σ Γ (array t 1) → LocalReference Σ Γ t + merge : LocalReference Σ Γ (array t m) → LocalReference Σ Γ (array t n) → Expression Σ Γ (fin (suc n)) → LocalReference Σ Γ (array t (n ℕ.+ m)) + slice : LocalReference Σ Γ (array t (n ℕ.+ m)) → Expression Σ Γ (fin (suc n)) → LocalReference Σ Γ (array t m) + cut : LocalReference Σ Γ (array t (n ℕ.+ m)) → Expression Σ Γ (fin (suc n)) → LocalReference Σ Γ (array t n) + cast : .(eq : m ≡ n) → LocalReference Σ Γ (array t m) → LocalReference Σ Γ (array t n) + nil : LocalReference Σ Γ (tuple []) + cons : LocalReference Σ Γ t → LocalReference Σ Γ (tuple ts) → LocalReference Σ Γ (tuple (t ∷ ts)) + head : LocalReference Σ Γ (tuple (t ∷ ts)) → LocalReference Σ Γ t + tail : LocalReference Σ Γ (tuple (t ∷ ts)) → LocalReference Σ Γ (tuple ts) + +data Statement Σ Γ where + _∙_ : Statement Σ Γ → Statement Σ Γ → Statement Σ Γ + skip : Statement Σ Γ + _≔_ : Reference Σ Γ t → Expression Σ Γ t → Statement Σ Γ + declare : Expression Σ Γ t → Statement Σ (t ∷ Γ) → Statement Σ Γ + invoke : (f : Procedure Σ Δ) → All (Expression Σ Γ) Δ → Statement Σ Γ + if_then_ : Expression Σ Γ bool → Statement Σ Γ → Statement Σ Γ + if_then_else_ : Expression Σ Γ bool → Statement Σ Γ → Statement Σ Γ → Statement Σ Γ + for : ∀ n → Statement Σ (fin n ∷ Γ) → Statement Σ Γ + +data LocalStatement Σ Γ where + _∙_ : LocalStatement Σ Γ → LocalStatement Σ Γ → LocalStatement Σ Γ + skip : LocalStatement Σ Γ + _≔_ : LocalReference Σ Γ t → Expression Σ Γ t → LocalStatement Σ Γ + declare : Expression Σ Γ t → LocalStatement Σ (t ∷ Γ) → LocalStatement Σ Γ + if_then_ : Expression Σ Γ bool → LocalStatement Σ Γ → LocalStatement Σ Γ + if_then_else_ : Expression Σ Γ bool → LocalStatement Σ Γ → LocalStatement Σ Γ → LocalStatement Σ Γ + for : ∀ n → LocalStatement Σ (fin n ∷ Γ) → LocalStatement Σ Γ + +data Function Σ Γ ret where + declare : Expression Σ Γ t → Function Σ (t ∷ Γ) ret → Function Σ Γ ret + _∙return_ : LocalStatement Σ Γ → Expression Σ Γ ret → Function Σ Γ ret + +data Procedure Σ Γ where + _∙end : Statement Σ Γ → Procedure Σ Γ + +infixl 6 _<<_ +infixl 5 _-_ _∶_ + +tup : All (Expression Σ Γ) ts → Expression Σ Γ (tuple ts) +tup [] = nil +tup (e ∷ es) = cons e (tup es) + +_∶_ : Expression Σ Γ (array t m) → Expression Σ Γ (array t n) → Expression Σ Γ (array t (n ℕ.+ m)) +e ∶ e₁ = merge e e₁ (lit (Fin.fromℕ _)) + +slice′ : Expression Σ Γ (array t (n ℕ.+ m)) → Expression Σ Γ (fin (suc m)) → Expression Σ Γ (array t n) +slice′ {m = m} e = slice (cast (+-comm _ m) e) + +_-_ : Expression Σ Γ t₁ → ⦃ isNum₁ : IsNumeric t₁ ⦄ → Expression Σ Γ t₂ → ⦃ isNum₂ : IsNumeric t₂ ⦄ → Expression Σ Γ (isNum₁ +ᵗ isNum₂) +e - e₁ = e + (- e₁) + +_<<_ : Expression Σ Γ int → (n : ℕ) → Expression Σ Γ int +e << n = e * lit (ℤ.+ (2 ℕ.^ n)) + +getBit : ℕ → Expression Σ Γ int → Expression Σ Γ bit +getBit i x = if x - x >> suc i << suc i